Realization of p-type gallium nitride by magnesium ion implantation for vertical power devices

Implementing selective-area p-type doping through ion implantation is the most attractive choice for the fabrication of GaN-based bipolar power and related devices. However, the low activation efciency of magnesium (Mg) ions and the inevitable surface decomposition during high-temperature activation annealing process still limit the use of this technology for GaN-based devices. In this work, we demonstrate successful p-type doping of GaN using protective coatings during a Mg ion implantation and thermal activation process. The p-type conduction of GaN is evidenced by the positive Seebeck coefcient obtained during thermopower characterization. On this basis, a GaN p-i-n diode is fabricated, exhibiting distinct rectifying characteristics with a turn-on voltage of 3V with an acceptable reverse breakdown voltage of 300V. Electron beam induced current (EBIC) and electroluminescent (EL) results further confrm the formation of p-type region due to Mg ion implantation and subsequent thermal activation. This repeatable and uniform manufacturing process can be implemented in mass production of GaN devices for versatile power and optoelectronic applications.Tis work was supported by the National Key R&D Program of China (No. 2016YFB0400105), the National Natural Science Foundation of China (Nos 91850112 and 61774081), the Natural Science Foundation of Jiangsu Province, China (Nos BK20161401 and BE2018115), and the Fundamental Research Funds for the Central Universities (Nos 021014380110 and 021014380135). We acknowledge access to NCRIS facilities (ANFF and the Heavy Ion Accelerator Capability) at the Australian National Universit